How to model a television dial?
A common way to do that is create a hole in the surface, add a circle into that space then fill in the gaps. 

1 : Subdivide a plane and delete some of the inner vertices.

2: Add a circle with a vertice count the same as the number of vertices that now make up the inner edges of the plane.

3: Select both the circle and the inner edges of the plane, then using the W shortcut key open the Specials menu and choose Bridge Edge Loops.

4: Using the Extrude tool model the rest of the Dial.

5: Add bevels and or supporting edge loops, smooth….. etc  etc .

Note that if you intend to use a Subsurf modifier then aim to use a circle with less vertices than in my example below.



Check on Youtube for cutting holes in meshes. This is a good example https://www.youtube.com/watch?v=Bc52fcrHvAA